﻿190 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  Nervous 
  system. 
  — 
  This 
  requires 
  special 
  methods 
  and 
  unusual 
  pains 
  in 
  

   determining 
  its 
  histological 
  character. 
  I 
  was 
  the 
  less 
  unwilling 
  to 
  let 
  

   this 
  omission 
  remain, 
  because 
  the 
  nervous 
  system 
  of 
  insects 
  has 
  been 
  

   the 
  subject 
  of 
  elaborate 
  histological 
  investigations 
  on 
  the 
  part 
  of 
  Pro- 
  

   fessor 
  Leydig, 
  235 
  of 
  Bonn, 
  to 
  whose 
  work 
  I 
  may 
  refer 
  those 
  who 
  are 
  de- 
  

   sirous 
  of 
  further 
  information 
  on 
  this 
  subject. 
  

  

  A 
  recent 
  article, 
  by 
  Hans 
  Schultze, 
  in 
  vol. 
  xvi, 
  page 
  57, 
  of 
  the 
  Archiv 
  

   fur 
  mikroskopische 
  Anatomie, 
  is 
  valuable. 
  There 
  is 
  also 
  an 
  extensive 
  

   memoir 
  by 
  K. 
  E. 
  Krieger, 
  236 
  on 
  the 
  nervous 
  system 
  of 
  the 
  crayfish, 
  and 
  

   another 
  by 
  Bellonci 
  237 
  on 
  that 
  of 
  Squilla. 
  

  

  In 
  order, 
  however, 
  to 
  illustrate 
  the 
  general 
  structure 
  of 
  the 
  nervous 
  

   ganglia, 
  I 
  have 
  given, 
  in 
  Fig. 
  11, 
  a 
  drawing 
  of 
  a 
  section 
  through 
  the 
  

   last 
  abdominal 
  ganglion 
  of 
  Oaloptenus. 
  The 
  figure 
  is 
  somewhat 
  dia- 
  

   grammatic. 
  A 
  ganglion 
  consists 
  of 
  two 
  parts, 
  the 
  central 
  fibrous 
  por- 
  

   tion, 
  from 
  which 
  the 
  nerves 
  arise, 
  and 
  the 
  peripheral 
  layer 
  of 
  ganglion 
  

   cells, 
  GZ. 
  On 
  each 
  side 
  of 
  these 
  are 
  two 
  nerve 
  roots, 
  one 
  the 
  dorsal, 
  DE, 
  

   the 
  other 
  the 
  ventral, 
  YE. 
  These 
  Professor 
  Semper, 
  238 
  in 
  his 
  article 
  on 
  

   strobilation 
  and 
  segmentation, 
  homologizes 
  with 
  the 
  roots 
  of 
  the 
  spinal 
  

   nerves 
  in 
  vertebrates, 
  but 
  I 
  do 
  not 
  know 
  how 
  far 
  his 
  conclusions 
  on 
  this 
  

   point 
  have 
  been 
  accepted 
  by 
  zoologists. 
  It 
  will 
  be 
  noticed 
  that 
  the 
  four 
  

   nerve 
  roots 
  in 
  Fig. 
  11 
  pass 
  out 
  from 
  the 
  central 
  fibrous 
  mass, 
  through 
  

   the 
  cellular 
  layer, 
  which 
  latter 
  is 
  thus 
  divided 
  into 
  four 
  fields. 
  

  

  The 
  structure 
  of 
  the 
  suprsesophageal 
  ganglion, 
  the 
  so-called 
  brain, 
  

   is 
  very 
  much 
  more 
  complicated 
  in 
  insects 
  than 
  was 
  formerly 
  supposed. 
  

   It 
  differs 
  very 
  essentially 
  from 
  any 
  of 
  the 
  abdominal 
  ganglia. 
  The 
  

   brain 
  of 
  insects 
  has 
  been 
  recently 
  investigated 
  by 
  Dietl, 
  239 
  Flogel, 
  240 
  and 
  

   Newton. 
  241 
  

  

  Grdber: 
  TTeber 
  die 
  tympanalen 
  Sinnesorgane 
  der 
  Orthopteren. 
  Denkschr. 
  Wien. 
  Akad., 
  Bd. 
  xxxvi, 
  

   (1876), 
  2 
  abtb., 
  p. 
  1. 
  

  

  : 
  TTeber 
  neue 
  Otocystenartige 
  Sinnesorgane 
  der 
  Insekten. 
  Arch, 
  fur 
  mikros. 
  Anat., 
  Bd. 
  xvi, 
  

  

  p. 
  36 
  (1878). 
  

  

  Mayer: 
  Sopra 
  certi 
  organi 
  di 
  senso 
  nelle 
  antenne 
  dei 
  Ditteri. 
  Mem. 
  Eeale 
  Accad. 
  dei 
  Lincei. 
  Roma, 
  4 
  

   Maggio, 
  1879. 
  (A 
  criticism 
  of 
  Graber's 
  paper 
  on 
  Otocysts.) 
  

  

  Grenadier: 
  Untersucbungen 
  iiber 
  das 
  Artbropodenauge. 
  Kliniscbe 
  Monatsblatter 
  fur 
  AugenbeiL 
  

   kunde, 
  Jabrg. 
  15, 
  Beilagebeft 
  zum 
  Maibeft, 
  1877. 
  

  

  Newton: 
  Eye 
  of 
  Homarus. 
  Quail. 
  Journal 
  Micros. 
  Sci., 
  1875. 
  

  

  Lowne 
  : 
  On 
  the 
  modification 
  of 
  the 
  simple 
  and 
  compound 
  eyes 
  of 
  Insects. 
  Phil. 
  Trans. 
  R. 
  Soc, 
  London, 
  

   vol. 
  169, 
  p. 
  577. 
  

  

  JBullar 
  : 
  On 
  the 
  Development 
  of 
  the 
  parasitic 
  Isopoda. 
  Phil. 
  Trans. 
  Boy. 
  Soc, 
  London, 
  voL 
  169, 
  p. 
  

   613, 
  514 
  (structure 
  of 
  eye). 
  

  

  Grdber: 
  TTeber 
  das 
  unicorneale 
  Tracheaten, 
  und 
  speciell 
  des 
  Arachnoideen- 
  und 
  Myriapodenauge. 
  

   Arch. 
  f. 
  micros. 
  Anat., 
  xvii, 
  p. 
  58 
  (1880). 
  

  

  238 
  Vom 
  Bau 
  des 
  Thierischen 
  Korpers, 
  Tubingen, 
  1864. 
  Histologic 
  des 
  Nervensysteme 
  der 
  Arthropo. 
  

   den, 
  pp. 
  214-226 
  ; 
  bei 
  Ortbopteren, 
  p. 
  262. 
  

  

  236 
  Krieger: 
  Uebor 
  das 
  Centralnervensystem 
  des 
  Flusskrebses. 
  Zeitsch. 
  f. 
  vdss. 
  Zool., 
  xxxiii 
  (1880), 
  

   p. 
  527. 
  Taf. 
  xxxi-xxxiii. 
  

  

  237 
  Bellonci, 
  G.: 
  Morfologia 
  della 
  systema 
  nervose 
  della 
  Squilla 
  mantis. 
  Annali 
  Museo 
  oivioo 
  stor. 
  

   Nat. 
  di 
  Genova, 
  vol. 
  xii 
  (1878), 
  pp. 
  518-545. 
  

  

  238 
  Semper: 
  Arbeitendes 
  Zool. 
  zoot. 
  Inst., 
  Wiirzburg, 
  Bd. 
  iii. 
  

  

  239 
  Dietl: 
  Die 
  Organisation 
  des 
  Artbropodongohirns. 
  Zeit. 
  f. 
  wiss. 
  Zoologie, 
  xxvii, 
  p. 
  488. 
  

   ™Fl'6gel: 
  TTeber 
  don 
  einboitlichon 
  Bau 
  des 
  Gehirns 
  in 
  den 
  verschiedenen 
  Inseotenordnungen. 
  

  

  Zeitsch. 
  f. 
  wias. 
  Zool., 
  Bd. 
  xxx, 
  Suppl. 
  (1877), 
  p. 
  556. 
  

  

  ™E. 
  T. 
  Newton: 
  On 
  the 
  brain 
  of 
  the 
  cockroaoh, 
  Blatta 
  orientalis. 
  Quatr. 
  Jour. 
  Micros. 
  Sci., 
  voL 
  xlx 
  

   1879), 
  p. 
  340. 
  

  

  